Paul,
I have quite a bit of experience running the 13b on natural gas.
In fact Mazda built 13b natural gas engine blocks back in the
'90's. There are still some here in my state still brand new in boxes.
I just bought two. During testing when I worked at RPI the 13b
would run 8k -10k on the stock seals. With ceramic seals the
time doubled. The natural gas engines come with ceramic seals and
9.7 compression. Another interesting thing about the natural
gas engines is they run so clean that they have omitted the
trailing ignition. The rotor housings only have one spark plug
hole. And the oil metering is half of a gasoline 13b. So the
engine is equipt with two spark plug distributor and only two
line oil metering.
Back in the day we did a test in the field with the Idaho fish
and wildlife for an indian tribe raising salmon. They needed
an engine to pump water from the river into tanks where they would
raise the fish and then put them into the river. The engine
had to run for six week straight. The requirements where no engine
pollution, no noise, and no evidence left behind when job was
finished. The team parked the 13b on a trailer near the stream
with a belt drive running a pump. A propane take was delivered
to the area and feed the engine. The engine had an audible horn
and light to tell when it was time to add the oil. A local
indian tribe member parked a small trailer next to the engine
trailer and kept the engine topped off. Worked great. Maybe you
could pass this along to Danny Perterson.
Thanks,Skip Gorman
Who do you get ahold of to buy an engine and how much?
Dale Davies
Thanks for the info Skip,
I was out of pocket for a few days. Like Dale I am curious how I
can get ahold of one or more of these boxed engines. Next
question, what type of reduction unit should be used? Danny Petersen
I remember someone selling the ceramic apex seals for these on ebay
last year.
Ed Carver
I was watching Hot Rod TV on Speed Channel this evening. They were
talking about a liquid propane injection system that Mother's developed.
Looks interesting. They were building a dragster with it.
http://www.autoblog.com/2007/10/31/sema-2007-1-000-hp-propane-
chevelle-by-mothers/
You'll have to glue the URL back together. Check it out.
They said it was way better than the gaseous propane version.
Mark LaPierre
Not that big a deal to do. Size injectors for the new fuel volume.
Works better that methanol in a diesel as it wants to vapourize.
Methanol wants to cool the air before it vapourizes and ends up
washing the cylinder walls. The LPG or LNG is a gas at ambient air
temps. LPG stays a liquid when colder than -40, does not matter C or
F because they are the same at that temp. LNG still will turn to gas
as it boils and condenses at -162C. One advantage of NG is that its
combustible limits in air are 5% to 15% which is a fairly narrow
range, very different than H2. The expansion during vapourization is
a problem should a tank be ruptured. LPG is similar in this respect.
Calgary Alberta had a school bus with kids running LPG rear ended a
number of years ago. Many were burned and killed due to the rapidly
expanding gas cloud. Very tragic.
Dale Davies
Dale, my Dad has a fuel injected V6 Mitsubishi duel fuel. The LPG
system runs through the original injectors, has a modified chip and
is "claimed" to produce the same power and that "seems" to be
correct but we haven't dyno tested it. What do you reckon ? carb
systems are down on power a bit and consume fuel 1:1.1 LPG the price
still makes it cheaper. Always warey of claims made by people trying
to sell you their product. There is also a lot of different names
for the same product which helps to confuse the issue. My sister-
inlaw has a dedicated LPG V8 ute, the petrol (gasoline, more
confusion) system has been removed altogether, a real bitch if you
run out of fuel, I'll check exactly how that is set up, me brother
is a mechanic so should just take a quick call. Seems that what is
new to you guys, could be old tech here. We have always been paying more
for petroleum (gasoline) and have copius quantities of LPG. Petrol is
$1.50/ltr, LPG is anywhere from 60cents/ltr city to 90cents/ltr
country and not available at all in the bush, go figure. ALL taxi's
(cabs) use LPG Graeme Riley
That one was OK.
Paul Lamar
Hi Graeme,
We have not taken to LPG here as our petrol (gasoline) has been cheap. In
Whitecourt, Alberta we are paying $1.139/L. In Vancouver on the west coast it
is $1.48/L due to different taxing and transportation. Oil has recently
dropped from $94/barrel to about $83 today. Our gasoline price will drop
eventually. They give us the story that it takes 3 months to go through the
system. Funny it usually only take a couple of weeks when the price goes up.
It also usually does not go down as far as the barrel price would indicate.
Thieving bastards.
I have not investigated the Mitsu dual fuel. I suspect the CR is higher than
standard and the timing is adjusted to compensate on gasoline. When running on
LPG the timing is advanced and the injector pulse width is longer to allow the
correct fuel ratio. LPG injected directly does not require much of a change to
the pulse width as the densities are semi close. Also the intake charge
cooling due to injecting and vapourizing the LPG in the intake creates a
denser charge in the cylinder which helps compensate any other power loss.
A dedicated LPG or LNG engine can be built with much higher compression than
usual and if done correctly give the same economy with much less expensive
fuel. It would be interesting to incorporate some of the Mazda Skyactiv tech
with LPG. You can use 13:1CR with conventional LPG. With the Skyactiv you
should be able to use 15:1CR or a bit more.
On a rotary, fill the depressions in the rotor and provide grooves for the
fuel mixture to transfer as a jet. 12:1 should be possible. I could see a car
engine with 375HP naturally aspirated.
Dale Davies
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